I'd say any p2p besides Direct Conncect++ sucks ass. I've never downloaded stuff off newsgroups or FTP's, but I don't know of any sites like that nor know anyone that does...
As for DC++, at least for the hubs I hang out in, people are very concerned about quality - I rarely have downloaded anything that was less than 192 kbps, and they're extremely dilligent about kicking people with fake files. It can be a lot slower than the others, but it's way more reliable. When I rip my own CD's, I always rip them into at least 192 VBR. The ability to browse people's file lists is a major advantage though, that way you definitely know if you're getting the whole album.